threads.java

package com.levelsbeyond;

import java.util.Date;
import java.util.concurrent.Callable;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * Thread Test
 */
public class App
{
	public static void main(String[] args) throws InterruptedException {
		ThreadPoolExecutor executor = new ThreadPoolExecutor(5, 5,
				10L, TimeUnit.SECONDS,
				new LinkedBlockingQueue<Runnable>());
		executor.allowCoreThreadTimeOut(true);

		runTasks(executor);

		System.out.println("Sleeping");
		Thread.sleep(15000);

		runTasks(executor);
	}

	private static void runTasks(ThreadPoolExecutor executor) {
		for (int i = 0; i < 10; i++) {
			executor.submit(new Callable<Object>() {
				@Override
				public Object call() throws Exception {
					System.out.println(String.format("Thread: %s, Time: %s", Thread.currentThread().getName(),
							new Date().toString()));
					return null;
				}
			});
		}
	}
}

Same with FixedThreadPool, except
executor.allowCoreThreadTimeOut(true);